To improve the safety aspects of vehicles, many manufacturers are now including side and curtain airbags. Side and curtain airbags may be employed in a vehicle side door, an A-pillar, a B-pillar, and other side structures and components of a vehicle. Side airbags are presently deployed in response to the information collected from side or lateral accelerometers and crush or pressure sensors. The accelerometers are used to determine or estimate severity of a collision and the pressure sensors are used to determine the condition of a vehicle or an estimated amount of intrusion into a vehicle of an object, after contact therewith. Upon receipt of the stated information, algorithms are used to evaluated conditions of a collision for restraint deployment.
For a 30 mph vehicle-to-vehicle collision, current deployment systems require a short activation time for restraint deployment, which is the time difference between when a host vehicle contacts an object and when a restraint is deployed. It is common for this period to be approximately 3-5 ms. From the onset of a collision, side airbags typically fully inflate in approximately 10-15 ms after activation. The stringent activation time requirements are due to the limited side structure of a vehicle and the limited available space between the interior side of the vehicle and an occupant, such as for example between an inside door panel and a vehicle occupant.
It is desirable to deploy airbags at different rates depending upon the severity of a collision. It is also desirable to deploy an airbag such that it is fully deployed at the appropriate time to maximize collision energy absorption and prevent injury to a vehicle occupant. It is understood that injury mitigation is not maximized when airbag deployment inaccurately occurs at an inappropriate time.
Also, current side airbag deployment systems, in certain scenarios, may be limited in their ability to differentiate between severe collisions and marginal collisions. For example, an accelerometer, installed in one selected area of a vehicle, may not detect or fully detect the energy experienced in a localized collision event in another or nearby area of the vehicle. Subsequently, non-deployment, or late deployment of side-restraints can occur.
Additionally, some airbag deployment systems, that include front airbags, can accidentally deploy the front airbags during a side collision. The National Automotive Sampling System indicates that 16% of frontal airbags have deployed for 3 o'clock side-collisions, while 22% of frontal airbags have deployed for 9 o'clock side-collisions.
Furthermore, current side airbag deployment systems do not account for occupant characteristics, such as occupant size, weight, and position within a seat system. As an example, it can be undesirable for a side airbag to deploy when an occupant is resting against a door panel or when a small occupant, such as a young child, is located in the seat system of concern.
Thus, there exists a need for an improved airbag deployment system for a vehicle that provides improved side airbag deployment control with accurate and appropriate deployment timing. The system should account for localized collisions, varying degrees of collision severity, and occupant characteristics, and prevent inadvertent deployment of front airbags during a side collision event.